Further, birds evolved endothermy, or warm-bloodedness independently of mammals, since the closest relatives of birds and mammals are themselves not endothermic. Because endotherms breathe in a lot of air, they tend to lose a lot of moisture through their lungs. Both birds and mammals have independently evolved respiratory turbinates in their nasal passages to trap water coming out of lungs and return the air back to the lungs. Lastly, both birds and mammals have 4 chambered hearts, but anatomical studies have shown that birds and mammals evolved them independently of one another because they differ in details and plumbing. I am sure there are other convergences, but what I have listed is ample proof that convergent evolution is quite common, since form follows function.
These seem to be general traits of many vertebrate animals- not just humans and birds- and are not similar enough to be considered convergent evolution. Many animals will rear their young, including many frogs, the legless, burrowing amphibians called caecillians, rodents, a good majority of all mammals, scorpions, communal skinks and, to an extant, some snakes. Some animals also have color vision comparable or even better than humans, and I believe that some birds are even capable of seeing UV radiation. Many more animals are diurnal. Degus are diurnal rodents (hence mammals) that can see a few different forms of light radiation including UV, and they care for their young. On top of that, birds are not truly bipedal like humans, and to an extent other apes such as gibbons, as a bird's balance is also supported by their tail, whereas greater and lesser apes including humans do not have a tail at all.
A good, proper example of convergent evolution would be like pill millipedes and pillbugs: One is a myriapod, being a millipede, while the other is a crustacean, and is more closely related to lobsters and crabs. Another would be the ancient ichthyosaurs and modern dolphins.
No, the similarities you see are a product of our shared environment. Two creatures that evolve in the same situation can adapt similarly, but do not necessarily have to be related. In the grand scheme of things, we might have all evolved from the same species of single celled organisms, but even that is very unlikely
I know that we are mammals, not birds, but I feel birds are like us in many ways - bipedal stance and locomotion (on the ground), parental care, good color vision and diurnality. So even though we are not closely related to birds, we have many similarities which indicates that we evolved in parallel to them. So can we consider humans and birds to be products of convergent evolution? Of course there are differences - (most) birds can fly, have feathers (not hair) and hollow bones.
